Noise abatement system for a gun

ABSTRACT

A noise abatement apparatus for a gun having a gun tube includes a plurality of generally spherical pressure vessels, with a first pressure vessel having an end adapted to be coupled to the gun tube. The pressure vessels are adapted for attenuating pressure waves caused by a firing of a projectile by the gun and for being mounted on a surface. At least two of the pressure vessels are in general alignment with one another. The apparatus may further include at least one connecting portion, a catcher for entrapping particulates and for permitting the projectile to pass, and at least one orifice plate or baffle for aiding in attenuating the sound. A noise abatement system includes the apparatus and a platform on which the apparatus is mounted. The system may further include an actuator for moving the apparatus along a track that is in physical communication with the platform.

This application is the U.S. National Phase application of InternationalApplication No. PCT/US02/12133, which claims priority of U.S.Provisional Application No. 60/285,220 filed Apr. 19, 2001.

FIELD OF THE INVENTION

The present invention relates to an apparatus and a system forminimizing the noise generated by the firing of a gun.

BACKGROUND OF THE INVENTION

Due to the increased population in the world, the noise generated by thetesting of guns in communities located near testing facilities of weaponsystems is becoming an increasing problem. As a result of this concern,there has been a need for a gun muffler or system for attenuating thegenerated noise level. Preferably, such a system should be able torapidly and safely attenuate the noise generated by the firing of aprojectile by a gun.

SUMMARY OF THE INVENTION

The present invention is directed to a noise abatement apparatus for agun having a gun tube. The apparatus includes a plurality of generallyspherical pressure vessels adapted for attenuating pressure waves causedby a firing of a projectile by the gun and for being mounted on asurface. A first of the pressure vessels has an end adapted to becoupled to the gun tube. At least two of the pressure vessels are ingeneral alignment with one another.

The apparatus may further include at least one connecting portion forconnecting a pair of the pressure vessels, a catcher disposed within thepressure vessels for entrapping particulates and for permitting theprojectile to pass, at least one orifice plate or baffle disposed in atleast one of the pressure vessels for aiding in attenuating the soundgenerated by the firing of the gun, and a plurality of rods attached toan end of the orifice plate.

According to a noise abatement system of the present invention, thesystem includes the apparatus 20, as described above, adapted for beingmounted on a platform. The system may further include an actuator, whichcan be used to move the apparatus along a track that is mounted on theplatform.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawings, in which:

FIG. 1 is a perspective view of an embodiment of a noise abatementsystem of the present invention;

FIG. 2 is a cut-away side sectional view, showing a first pressurevessel of a noise abatement apparatus in relation to a gun muzzle of agun, taken along cut line 2 of FIG. 1;

FIG. 3 is a longitudinal side elevational view of an embodiment of anoise abatement apparatus of the present invention mounted on aplatform;

FIG. 4 is a longitudinal side elevational view of the noise abatementapparatus shown in FIG. 3, with at least a portion of the shell of eachpressure vessel removed;

FIG. 5 is an end view of the noise abatement apparatus shown in FIG. 4;

FIG. 6 is an enlarged view of an orifice plate or baffle of the noiseabatement apparatus shown in FIG. 4; and

FIG. 7 is an enlarged view of a hinge of the platform shown in FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, an embodiment of a noise abatementapparatus 20 includes a plurality of pressure vessels, preferably threepressure vessels 22, 24, 26, which are preferably substantiallyspherical in shape and in alignment with one another. Preferably, thenoise abatement apparatus 20 comprises three spherical pressure vessels22, 24, 26 that are of decreasing size from the entry end of theprojectile to the exit end of the projectile. The apparatus 20 alsoincludes legs 28, 30, 32 for mounting each of the pressure vessels 22,24, 26 on a platform 33.

The noise abatement apparatus 20 can be adapted and sized for a numberof different guns 12. In one embodiment, namely, when the noiseabatement apparatus 20 is 3 meters in length and weighs approximately685 kg, the noise abatement system 10 may be used for 25, 35, and 40 mmguns. For such guns, it has been found that the muffler attenuation of aminimum of 12 dBA at a distance of 250 meters all directions from thegun can be achieved. The material of the pressure values may be anyknown material for this purpose but is preferably carbon steel 517.

In a preferred embodiment of the apparatus 20, the first two pressurevessels 22, 24 (“first” referring to closer to the entry end of theprojectile) have internal orifices/baffles, such as those described inU.S. Pat. No. 5,398,589 or U.S. Pat. No. 5,686,688, both of which areincorporated herein by reference. As an example of the internalorifices/baffles, an orifice plate (not shown) may be at about thecenter of the first pressure vessel 22 which is coupled to the secondpressure vessel 24. The orifice plate is an annular disk defining acentral circular hole through which the projectile passes. The size ofthe hole is dictated by the size of the projectile. Also, if the hole istoo small, it is difficult to rapidly vent the chamber of the firstpressure vessel 22 (or of the second pressure vessel 24) through thehole and out through the port by way of the exhaust blower. On the otherhand, if the hole of the orifice plate is too large, the muffling ofsound is not sufficient.

As another example of the internal orifices/baffles, the baffles (notshown) are generally conical in shape, having a diameter which linearlydecreases from the entry end of the chamber of the first pressure vessel22 (or the second pressure vessel 24) to the exit end of the chamber ofthe first pressure vessel 22 (or the second pressure vessel 24). Eachbaffle may abut against the orifice plate. A retaining wall may becoupled to the chamber of the first pressure vessel 22 (or the secondpressure vessel 24), and each orifice plate may be mounted to theretaining wall by way of straps and nuts and bolts. Similar to theorifice plate of the first example, the orifice plate defines a centralhole through which a projectile passes. The diameter of the hole isdefined by similar functional requirements as the diameter of the holeof the orifice plate of the first example.

Alternatively, the baffles 34, 36, 38 may be those shown in FIGS. 3 and7, namely, consisting of a steel plate 40 (for baffle 34; not shown forbaffles 36, 38) with a number of bars 42 (for baffle 34; not shown forbaffles 36, 38), such as with twelve bars, welded to the plate. Thesebars 42 serve to improve the diffusion of the gas from the gun 12. Theymay either be mounted only to the plate 40 or mounted to the plate 40 atone end and welded to the inside wall of the sphere 22 at their otherends, as shown in FIG. 3.

According to the present invention, an embodiment of a noise abatementsystem 10 includes the noise abatement apparatus 20 as described above,as well as a track or tracks 44 mounted on a horizontal concrete pad orslab 46 and an actuator 48 for driving the platform 33 along the tracks44.

The pressure vessels 22, 24, 26 are mounted on the platform 33, which asshown consists of an upper steel frame 50 which is attached preferablyby a hinge 52 at the entry end 54 to a lower frame 56. The attachment bythe hinge 52 allows for the upper frame 50 to be spaced from the lowerframe 56 closer to the exit end of the apparatus 20. This can beachieved by adjusting elevation adjustment 58 or azimuth adjustment 59as shown by, for example, screws, a jack system, or a hydraulicmechanism (not shown) or some other means. The lower frame 56 has fourlegs 60 attached, preferably at its corners, with wheels 62 as shown atthe lower end of the legs 60. The wheels 62 preferably are grooved andcan ride on the steel tracks 44, which itself is attached to theconcrete pad or slab 46 embedded in or mounted to the ground.Preferably, the actuator 48 is an electrical actuator, which can be anelectric screw jack, may be mounted on the concrete pad or slab 46 andattached to the lower frame 56 to allow for the apparatus 20 to be movedback and forth along the tracks 44.

The pressure vessels 22, 24, 26 can be separated from each other atcylindrical connecting portions 64, 66, which can be bolted together.Preferably, the diameter of each of the connecting portions 64, 66 isgreater than the diameter of the gun muzzle 14. In addition, thepressure vessels 22, 24, 26 can be separated from the mounting frame orplatform 33 by disconnecting the legs 28, 30, 32 from the upper frame50, and then completely disassembled by opening them along their halves(as two clam shells) so that they can be easily inspected or repaired,if required. The first pressure vessel 22 incorporates a sabot catcher68 (namely, a steel plate contoured to the internal wall of the firstpressure vessel 22) that can be replaced as required by disassemblingthe first pressure vessel 22. The first pressure vessel 22 also has anexhaust port 70 with an exhaust blower (not shown) to remove anyaccumulation of exhaust gas, just as shown and described in U.S. Pat.No. 5,398,589 or U.S. Pat. No. 5,686,688. This can be mounted at anysuitable place on the first pressure vessel 22, typically at the top ofthe vessel 22 with a vent stack (not shown).

The muzzle 14 of the gun 12 being fired projects into the first pressurevessel 22 that incorporates a seal 72 to prevent any gas blowback, whilenot creating any frictional drag on the recoil of the gun. The seal 72may have a configuration as shown and described in U.S. Pat. No.5,398,589 or U.S. Pat. No. 5,686,688 or any other suitableconfiguration. For example, the seal 72 may be a sliding seal in theform of a lamination, with each layer of the lamination consisting of amaterial which is rendered flexible by a plurality of radially extendingslots, with the slots offset from one another from layer to layer.Different seals will be utilized for various caliber guns being fired.

The electrical actuator 48 moves the cradle on the rail and positionsthe muzzle 14 of the gun 12 being fired in engagement with the seal 72.The muzzle 14 is made accessible for bore siting by moving the cradle toexpose the muzzle 14.

The system and apparatus can be modified by adding any portion or aspectof U.S. Pat. No. 5,398,589 or U.S. Pat. No. 5,686,688 thereto.

What is claimed is:
 1. A noise abatement system for a gun having a guntube, said system comprising: a platform; and a plurality of generallyspherical pressure vessels adapted for attenuating pressure waves causedby a firing of a projectile by the gun and for being mounted on saidplatform, wherein said plurality of pressure vessels are in generalalignment with one another and a first pressure vessel of said pluralityof pressure vessels has an end adapted for coupling to the gun tube. 2.The noise abatement system according to claim 1, wherein said platformcomprises an upper frame and a lower frame wherein said upper frame isattached to said lower frame by a hinge disposed about said end adaptedfor coupling to the gun tube.
 3. The noise abatement system according toclaim 2, further comprising an adjustor for effecting an angularseparation between said upper frame and said lower frame about saidhinge.
 4. The noise abatement system according to claim 2, furthercomprising a track mounted on a horizontal slab and an actuator fordisplacing said plurality of pressure vessels along said track, whereinsaid lower frame comprises a plurality of legs comprising a plurality ofwheels adapted for riding on said track.
 5. The noise abatement systemaccording to claim 4, wherein said slab is made of concrete.
 6. Thenoise abatement system according to claim 4, wherein said track is madeof steel.
 7. The noise abatement system according to claim 1, furthercomprising a track mounted on a horizontal slab and an actuator fordisplacing said plurality of pressure vessels along said track, whereinsaid platform comprises a plurality of legs comprising a plurality ofwheels adapted for riding on said track.
 8. The noise abatement systemaccording to claim 7, wherein said slab is made of concrete.
 9. Thenoise abatement system according to claim 7, wherein said track is madeof steel.
 10. The noise abatement system according to claim 1, whereinsaid plurality of pressure vessels is three generally spherical pressurevessels.
 11. The noise abatement system according to claim 10, whereinat least two of said three generally spherical pressure vessels are ofdifferent sizes.
 12. The noise abatement system according to claim 10,wherein said plurality of pressure vessels are of decreasing size in adirection of travel of the projectile.
 13. The noise abatement systemaccording to claim 1, wherein said plurality of pressure vessels aremounted on said platform by a plurality of legs.
 14. The noise abatementsystem according to claim 1, wherein said first pressure vessel furtherhas a seal for preventing the escape of residual combustion gases causedby a firing of the projectile by the gun.
 15. The noise abatement systemaccording to claim 1, further comprising at least one connecting portionfor connecting a pair of said plurality of pressure vessels.
 16. Thenoise abatement system according to claim 1, further comprising acatcher disposed within said plurality of pressure vessels forentrapping particulates and for permitting the projectile to pass. 17.The noise abatement system according to claim 1, further comprising atleast one orifice plate being adjustable relative to said plurality ofpressure vessels, wherein said orifice plate is disposed in at least oneof said plurality of pressure vessels for attenuating pressure waves.18. The noise abatement system according to claim 17, further comprisinga plurality of rods attached to an end of said orifice plate.
 19. Thenoise abatement system according to claim 18, wherein said plurality ofrods are further attached to an inside wall of one of said plurality ofpressure vessels.
 20. A noise abatement apparatus for a gun having a guntube, said apparatus comprising a plurality of generally sphericalpressure vessels adapted for attenuating pressure waves caused by afiring of a projectile by the gun and for being mounted on a surface,wherein at least two of said plurality of pressure vessels are ingeneral alignment with one another and a first pressure vessel of saidplurality of pressure vessels has an end adapted for coupling to the guntube.
 21. The noise abatement apparatus according to claim 20, whereinsaid plurality of pressure vessels is three generally spherical pressurevessels.
 22. The noise abatement apparatus according to claim 21,wherein at least two of said three generally spherical pressure vesselsare of different sizes.
 23. The noise abatement apparatus according toclaim 21, wherein said plurality of pressure vessels are of decreasingsize in a direction of travel of the projectile.
 24. The noise abatementapparatus according to claim 20, wherein said plurality of pressurevessels are mounted on the surface by a plurality of legs.
 25. The noiseabatement apparatus according to claim 20, further comprising a seal forpreventing the escape of residual combustion gases caused by a firing ofthe projectile by the gun.
 26. The noise abatement apparatus accordingto claim 20, further comprising at least one connecting portion forconnecting a pair of said plurality of pressure vessels.
 27. The noiseabatement apparatus according to claim 20, further comprising a catcherdisposed within said plurality of pressure vessels for entrappingparticulates and for permitting the projectile to pass.
 28. The noiseabatement apparatus according to claim 20, further comprising at leastone orifice plate being adjustable relative to said plurality ofpressure vessels, wherein said orifice plate is disposed in at least oneof said plurality of pressure vessels for attenuating pressure waves.29. The noise abatement apparatus according to claim 28, furthercomprising a plurality of rods attached to an end of said orifice plate.30. The noise abatement apparatus according to claim 29, wherein saidplurality of rods are further attached to an inside wall of one of saidplurality of pressure vessels.